Final answer:
George Beadle formulated a hypothesis about the relationship between genes and eye color in Drosophila.
Step-by-step explanation:
The hypothesis formulated by George Beadle while studying eye color mutations in Drosophila is that the eye color phenotype is determined by specific genes located on the X chromosome. He proposed that different alleles of these genes can result in variations in eye color, such as wild-type (red eyes) or mutant (black or cinnabar eyes). By conducting crosses and analyzing the inheritance patterns of eye color in Drosophila, Beadle aimed to determine the relationship between specific genes and eye color.